A blood coagulation examination is conducted for grasping a clinical condition of a coagulation-fibrinogenolysis system, diagnosing disseminated intravascular coagulation (DIC), confirming a therapeutic effect on thrombus, and diagnosing hemophilia. In particular, measurement of blood clotting time is an examination that directly checks whether a coagulation reaction generating fibrin correctly functions. The blood clotting time is prolonged in a case where there is a congenital or acquired abnormality.
Therefore, the blood coagulation examination is important as a means for checking, with screening, a bleeding tendency caused by various factors, such as abnormalities of a blood coagulation factor and a von Willebrand factor, hepatopathy, vitamin K deficiency, production of an inhibitor, and DIC.
Conventionally, the blood coagulation examination is conducted by visually capturing fibrin precipitation which is an end point of the blood coagulation reaction. Since the 1960s, an automatic analyzing apparatus developed for improvement of the processing number of specimens and high precision, has been used for an ordinary examination.
For example, an electric resistance detecting method, an optical method, and a mechanical method are mainly used for detecting fibrin precipitation by the automatic analyzing apparatus. The optical method (transmitted light detection, and scattered light detection) and the mechanical method (viscosity detection) that have excellent processing performance, have been mainly used.
In a clinical examination field, a measurement result of a patient specimen is required to be reported as soon as possible.
In relation to this, in measurement of a substance to be measured included in a sample by an automatic analyzing apparatus, the following calculating method has been known. A parameter in an approximate expression is calculated using a measurement value that varies with time. Then, the degree of convergence of reaction is determined in accordance with the degree of convergence of the parameter. A measurement value at the end of the reaction is calculated using a parameter at the time when it is determined that the reaction has converged (for example, refer to PTL 1).
As a result, measurement time can be changed for each specimen, and processing performance can be improved.